United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park, NC 27711
Research and Development
EPA/600/SR-95/013 February 1995
EPA Project Summary
Air Infiltration Measurements
Using Tracer Gases: A Literature
Review
MaxM. Samfield
The report gives results of a litera-
ture review of air infiltration measure-
ments using tracer gases, including
sulfur hexafluoride, hydrogen, carbon
monoxide, carbon dioxide, nitrous ox-
ide, and radioactive argon and kryp-
ton. Sulfur hexafluoride is the
commonest tracer gas, primarily be-
cause its presence may be accurately
measured in the parts per billion
range, while most of the other gases
used may be accurately measured in
the parts per million range. The re-
port describes a computer-controlled
injection system.
This Project Summary was developed
by EPA's Air and Energy Engineering
Research Laboratory, Research Triangle
Park, NC, to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title (see Project Report ordering infor-
mation at back).
The use of tracer gases for the mea-
surement of air infiltration into structures
and interzonal flows within a structure is
not new. This technique has been investi-
gated over the past 15 years. Numerous
tracer gases have been used, among
which are sulfur hexafluoride, hydrogen,
carbon monoxide, carbon dioxide, nitrous
oxide, and radioactive argon and krypton.
Sulfur hexafluoride is the most common
tracer gas of choice—primarily because
its presence may be accurately measured
in the parts per billion range using elec-
tron capture/gas chromatography tech-
niques. Most of the other gases used may
be accurately measured in the parts per
million range using infrared technology.
There are generally three types of
methods used: tracer gas decay, con-
stant concentration, and constant injec-
tion. Investigations comparing tracer
gases have led to the following conclu-
sions: (a) Even though sulfur hexafluo-
ride is appreciably heavier than air,
mixing is not a problem; and (b) The
inherent uncontrollable variables present
in tracer gas work limit the accuracy of
determinations to +5-10%. There is thus
no reason why one tracer gas should
be selected over another provided other
criteria are met. In the case of hydro-
gen, diffusion of the gas through the
surrounding walls can pose a problem.
Tracer gases may be used in air flow
measurements in large buildings where
the building may be treated as several
coupled zones. In such a case, the decay
technique can still be used by having the
system repeat the injection at regular in-
tervals. A computer-controlled injection
system is described in the full report.
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Max M. Samfield, Durham, NC 27701, is an independent consultant.
David C. Sanchez is the EPA Project Officer (see below).
The complete report, entitled "Air Infiltration Measurements Using Tracer Gases: A
Literature Review,"(Order No. PB95-173225; Cost: $17.50, subject to change)
will be available only from
National Technical Information Service
5285 Port Royal Road
Springfield, VA22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at
Air and Energy Engineering Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
Penalty for Private Use
$300
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
EPA/600/SR-95/013
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